Metalica tone with boss metal zone or EMGs?

i have a Mesa boogie triple rectifier and 2 metal zone pedals running into it, but I don't have any guitars with EMGs. Would it be better to get Metallica tone by replacing my guitars with EMGS or buying 1 more metal zone pedal ?

Ditch the metal zones and get yourself an EMG 81 in the bridge. The triple rectifier alone is enough. If you want a little extra, run any tubescreamer or tubescreamer copy in front. Anything from a bad monkey to a maxon od808 will do. The earlier Metallica sound Master of Puppets through Black Album is Mark series. Kirk started using the Dual Rectifier in the rackmount version in the mid '90s. I believe he still has two in his live rack. Kirk and Hetfield also use the Triaxis which has both Mark and Rectifier circuits. If you want to keep running the metal zone, just turn down the distortion on the pedal all the way and use the eq and level controls. The whole idea behind having a Rectifier or other high gain amp is to not have to use a distortion pedal.

edit: Metallica does not use that much gain. Don't go higher than 12 o'clock-1:30 on the gain in modern mode. Keep the treble around 1 o'clock, middle at 10:30-11, bass 10 o'clock, presence at 12 o'clock or less. Set the channel master at least at 9 o'clock and the output 10 o'clock if possible. The more volume you have, you will notice that the sound gets fuller and thicker and you don't need to crank the gain.

P.S. Watch some to YouTube videos where Kirk and James are playing by themselves. You will hear that the sound doesn't have that much gain. On the albums they record 4 guitars at least for the rhythm parts. This is why the albums sound so huge.